jisamaniac... Those figures are not correct for this application. HD Video uses a different system to represent colour depth/bits than your standard computer based bit-depth system.
Normal HD video signals, like that you find on BluRay etc., use 8-bit, so for each pixel the image contains 8-bits each for red, green and blue... giving 24 bits total. subsequently there are 256 8-bit binary numbers possible, so you end up with 256 shades each of R, G and B. Combine them together you achieve 16,777,216 possible colors, 256x256x256.
10-bit color gives you 1,024 shades of each R, G and B with over a billion possible colors. 12-bit gives you 4,096 shades, thus 68 billion colors., and so on.